Novel phase transitions in B-site doped manganites

Abstract: We have examined the infrared reflectivity and the electrical resistivity of La1− x [Sr(Ba)] x Mn1– z [Cu(Zn)] z O3 samples in ferromagnetic metallic and insulator regime. Several phase transitions are observed, the most obvious being the transition from a ferromagnetic metallic to a ferromagnetic insulator phase that is related to the formation of short-range orbitally ordered domains. The temperature T 1 of the phase transition is dependent on doping concentration and for optimally doped samples (~32% of Mn4+ ions) we have found T 1≈0.93 T C. [Copyright &y& Elsevier]